Stock-Based Compensation

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Stock-based compensation expense is included in the following line items in the condensed consolidated statements of operations (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Sales and marketing	$	534	$	301	$	1,385	$	855
General and administrative	1,714		1,191		4,762		3,700
Research and development	2,787		1,965		8,574		5,115
Total stock-based compensation expense	$	5,035	$	3,457	$	14,721	$	9,670

The following table summarizes the components of non-cash stock-based compensation expense (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Stock options and assumed options	$	941	$	850	$	2,836	$	2,666
Restricted stock units	4,046		2,585		11,746		6,900
Restricted stock awards	—		—		—		1
Employee stock purchase plan	48		22		139		103
Total stock-based compensation expense	$	5,035	$	3,457	$	14,721	$	9,670
Tax benefit from stock-based awards	$	565	$	2,958	$	4,050	$	6,899

We granted an aggregate of 30,000 and 140,500 stock options pursuant to our 2015 Equity Incentive Plan, or the 2015 Plan, during the three and nine months ended September 30, 2019, respectively, as compared to an aggregate of 4,000 and 180,500 stock options for the same periods in the prior year. There were 60,043 and 258,668 stock options exercised during the three and nine months ended September 30, 2019, respectively, as compared to 281,709 and 721,573 stock options for the same periods in the prior year. We granted an aggregate of 88,308 and 425,324 restricted stock units during the three and nine months ended September 30, 2019, respectively, as compared to an aggregate of 54,300 and 266,470 restricted stock units for the same periods in the prior year. There were 15,880 and 177,946 restricted stock units that vested during the three and nine months ended September 30, 2019, respectively, as compared to 8,168 and 21,714 restricted stock units vested during the same periods in the prior year.